ESPs are a main type of artificial lift being used to unload current horizontal unconventional wells. Due to their high cost and high failure rate an operator must implement them in the most efficient manner possible. This paper addresses a way to create a solution to make ESPs more efficient by using compression at surface. Current ways of handling gas through ESPs are insufficient utilizing variable speed drives (VSDs). Additional gas handling equipment installed in ESPs have also encountered mixed results as designs continue to be tinkered to improve gas handling. One area that has not been researched extensively is utilizing compression to drawdown the casing annulus of a well on ESP. A preferential path of less static head pressure allows the gas to be drawn up the annulus rather than handled through the pump. Thereby alleviating gas handling problems in the ESP and raising the FL over the pump. The paper presents two case studies in Oklahoma involving ESP compression assistance up the annulus: one is a case study of an unconventional well of the Mississippi Lime with a low FL and moderate gas production, the second is an unconventional well in the Meramec formation with large amounts of gas production that was increased with the assistance of a compressor to the ESP. Data was collected over a six-week period and ESP performance is compared before and after the surface compressor installation for case 1. In case 2, well performance is compared for 3 different artificial lift setups: gas lift, ESP, and compression assisted ESP over a 3-month period. Both case studies show benefits for utilizing surface compression with an ESP. The biggest benefits were found to be increased production and reduced operating cost by extending ESP longevity.

Approximately 40% of unconventional wells in the United States with artificial lift are using gas lift. One of the blessings of gas lift is that it is very forgiving and rarely fails. This has led some operators to the conclusion that gas lift doesn’t require a proper control and optimization scheme. The objective of this study is to use field data and show the importance and benefit of a controlled and optimized gas lift compressor to aid production. The intelligent gas lift compressor utilizes a heavy computational process of taking a composite Vogel reservoir inflow model coupled with a Hagedorn & Brown outflow model that informs the Guo model to solve for a minimum critical rate to lift liquid droplets out of the wellbore. First, an empirical range of injection rates is used to find the rate with maximum unloading as indicated by a drop in casing injection pressure. Once this rate is found, reservoir inflow performance relationship (IPR) parameters are estimated to meet that condition. These parameters are held constant for a time period and injection rate needed is calculated based on production rate and pressure coming into the programmable logic controller (PLC) via digital connections. This approach is tested on a well and the production is monitored over a 3-month period. The collected data are used to analyze the benefits of an intelligent gas lift compressor control. The data from a well with this intelligent gas lift system is monitored over a 3-month period. This includes a 20-day period of the compressor searching for an injection rate that shows to be the most efficient. Then the compressor control is set up with a critical rate control mode. This calculation is performed with an edge server that runs the intense calculations every minute to instruct the compressor what volume of injection it needs to achieve manipulation of an automated suction control valve and speed control of the engine driver. The surface casing pressure data shows a very stable unloading behavior profile, which is confirmed with very stable oil and gas production data over the observation period. An estimate of gained production during the periods of high line pressure along with stable unloading is given as the justification for outfitting the well site with the intelligent compressor controls. Despite gas lift’s importance as a lift technique, its control and optimization are still not properly addressed within the industry. This work’s proposed intelligent gas lift scheme can be a potentially valuable solution to unstable unloading of liquids, and benefit the operators significantly in production and revenues.